Arid regions or regions that experience dry seasons are often reliant on ground water reserves for non-potable water for use in horticulture and for watering parks and gardens. It is a common problem in some regions with such ground water, that it contains dissolved iron, usually dissolved in ferrous (Fe2+) form. This will oxidise to ferric form on exposure to air, leading to staining of surfaces on which the bore water contacts. A more serious problem, and one which this invention seeks to address, is where iron is oxidised to ferric form by microbial action. The iron is incorporated in a slime which is deposited on internal parts of reticulation systems such as pumps, valves, and pipes etc. Not only can bacteria utilise dissolved iron, but can also oxidise iron contained in internal parts of reticulation systems, leading to early equipment failure. The presence of these deposits also leads to reduced performance, blockages, and failure of valves and sprinklers.
Various solutions have been proposed to iron build-up in reticulation systems. For example, hydrochloric acid has been used, but problems are experienced including severe corrosion leading to unserviceability, generation of noxious gasses, and also safety issues with handling. In addition, industrial grade hydrochloric acid can often be contaminated with impurities which can present a risk to the environment. It has been found also that hydrochloric acid is not particularly effective against biofouling deposits.
Phosphoric acid has also been used, but has been found to have similar disadvantages to hydrochloric acid, and in addition, has the disadvantage of adding phosphorus to the environment. Phosphorus in the environment is a known contributor to algal blooms.
It is an object of the present invention to provide a composition and method for treating underwater equipment to remove or minimise build-up of such deposits.
The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia or elsewhere as at the priority date of the application.
Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.